Alternating Electric Field-Assisted Matrix Nano-Coating for High Spatial Resolution MALDI Imaging.

Area of Science:

• Analytical Chemistry
• Biophysics
• Mass Spectrometry

Background:

• Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is crucial for exploring endogenous compounds.
• Achieving simultaneous matrix nano-coating and in situ analyte enrichment is vital for high-resolution imaging.
• Current methods face limitations in uniform matrix deposition and efficient analyte enrichment.

Purpose of the Study:

• To develop a novel matrix coating approach to enhance MALDI-MSI capabilities.
• To improve in situ ionization efficiency and high-resolution imaging of endogenous compounds.
• To demonstrate the versatility of the new method across diverse biological samples.

Main Methods:

• Alternating electric field-assisted matrix nano-coating (AEFAMnC) was developed.
• AEFAMnC utilizes asymmetric alternating electric fields for repetitive forced micro-extraction.
• The method was applied to rat brain, germinating Chinese yew seeds, and single cells.

Main Results:

• AEFAMnC achieved matrix nano-coating with the smallest crystal size (ca. 70 nm) and superior uniform deposition.
• The method significantly enhanced in situ analyte enrichment through repetitive forced micro-extraction.
• Improved ionization efficiency and high-resolution (5-µm pixel size) imaging of endogenous compounds were achieved.

Conclusions:

• AEFAMnC simultaneously achieves matrix nano-coating and in situ analyte enrichment, a first for MALDI-MSI.
• This novel approach significantly enhances the performance of high-spatial-resolution MALDI-MSI.
• AEFAMnC holds significant implications for high-resolution MALDI imaging, especially in single-cell spatial omics.